更新 app.ts

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: huangyiirene

packages/foundation/core/src/app.ts

@@ -47,7 +47,7 @@ export class ObjectQL implements IObjectQL {
     private actions: Record<string, ActionEntry> = {};
 
     // ObjectStack Kernel Integration
-    private kernel: ObjectStackKernel | null = null;
+    private kernel: ObjectStackKernel;
     private kernelPlugins: any[] = [];
 
     // Store config for lazy loading in init()